In a large bowl, combine the ground beef, egg, almond flour, nutritional yeast, sea salt, black pepper, garlic powder, and onion powder.
Gently mix the ingredients by hand until just combined, being careful not to overwork the meat.
Roll the mixture into approximately 8 to 10 evenly sized meatballs.
Heat the olive oil in a large skillet over medium-high heat.
Add the meatballs to the skillet and sear for 2-3 minutes per side until a golden-brown crust forms.
Pour the marinara sauce over the meatballs, reduce heat to low, and cover the skillet.
Simmer for 8-10 minutes until the meatballs are cooked through and the sauce is bubbling.
While the meatballs simmer, lightly sauté the zucchini noodles in a separate pan for 2 minutes until just tender.
Serve the meatballs and sauce over the zucchini noodles and garnish with fresh parsley.